This pilot study tested the hypothesis that exercising on a wheelchair accessible treadmill improves cardiovascular fitness for manual wheelchair users without adverse effects on propulsion biomechanics or shoulder pain. Three manual wheelchair users participated in 30 minute exercise sessions three times per week for six-weeks using self-selected programs on a wheelchair accessible treadmill. Exercise capacity and propulsion biomechanics were assessed before and after the six week program. On average, subjects displayed increases in maximum VO₂ (22.9%) and maximum heart rate (9.6%), while resting heart rate decreased (14.7%). Propulsion biomechanics and shoulder pain did not change. There were no adverse effects associated with extended use of the treadmill. The results suggest that persons with paraplegia can improve cardiovascular fitness through the regular aerobic exercise with a wheelchair accessible treadmill.